Re: [Mimedefang] PGP encyption of outging email

2009-05-07 Thread Paul Murphy

Steffan wrote:

 I wonder why you don't want to encrypt/sign in the MUA. It is more 
 flexible and, well, works most of the time.

Because users are incapable of getting it right, and the time they forget to
encrypt the message may also be the time they send company B's confidential
data to company A.  At one point I was seeing ~10 messages per week which the
users had forgotten to encrypt, and I saw 2 in 6 months go to the wrong
company without encryption.

I looked at this a long time ago, and got a system working which verified
that messages to and from designated domains were encrypted.  It was a bit
messy, but it worked.  It also ensured that the corporate key had been
included in the encryption targets, so we could enforce use of this key for
message recovery purposes.  It did this by trying to decrypt any encrypted
parts using the corporate key.  Coincidentally, this also stopped employees
using encryption to any domain except those we expressly permitted it to -
otherwise our confidential data could walk out of the door, and we'd be none
the wiser.

The issue, as Steffan has already pointed out, is that you have to trust your
mail server with the passphrase to your private key, or in our case, to the
company's private key.  In our circumstances, this was more acceptable than
the breaches of security caused by incapable users, but you may not be able
to make that argument.

Best Wishes,

Paul.
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Re: [Mimedefang] PGP encyption of outging email

2009-05-07 Thread Andrzej Adam Filip
Steffen Kaiser skmimedef...@smail.inf.fh-bonn-rhein-sieg.de wrote:

 On Wed, 6 May 2009, pete wrote:

 Is there a method for encrypting outgoing email using PGP (or other
 methods). I am thinking of doing this on a per recipient basis. I.e encrypt
 email to people I regularly email and leave plain the rest.

 If you search CPAN, you find tons of PGP / GnuPG modules unfortunatly. I 
 made a quick search for PGP  MIME (so you don't fiddle with the MIME 
 structure yourself) and there are a few as well, e.g. Mail::GnuPG.

 The most problem I see is that you have to open your secret key to 
 MIMEDefang. As I understand your mail so, that you are using a 
 single-person system, this drops down to how secure your server is and if 
 you trust the system to hold your key without passphrase or in
 pgp-agent.

To encrypt outgoing email only public key (of the recipient) is required.
Secret/private key (of sender) is required for *signing*.

 [...]

-- 
[plen: Andrew] Andrzej Adam Filip : a...@onet.eu
The time spent on any item of the agenda [of a finance committee] will be
in inverse proportion to the sum involved.
  -- C. N. Parkinson
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Re: [Mimedefang] PGP encyption of outging email

2009-05-07 Thread Richard Laager
On Thu, 2009-05-07 at 09:17 +0100, Paul Murphy wrote:
 Steffan wrote:
 
  I wonder why you don't want to encrypt/sign in the MUA. It is more 
  flexible and, well, works most of the time.
 
 Because users are incapable of getting it right, and the time they forget to
 encrypt the message may also be the time they send company B's confidential
 data to company A.

You might want to consider checking that the message is encrypted and
rejecting if it is not. That's probably WAY simpler and has the
side-effect of educating users on your policy.

Richard


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[Mimedefang] Mimedefang + Spamassassin but no X-Spam-Score

2009-05-07 Thread Ngo, Toan
I've been getting emails with bad attachments being dropped by Mimedefang.  The 
issue is that the email is SPAM but is not being tested by Spamassassin since 
there doesn't seem to be an X-Spam-Score in the headers.  The original message 
size is about 120KB according the sendmail logs.  Is it a Mimedefang config 
option that I'm missing?  I would like Mimedefang to still have Spamassassin 
test the email even if there was a dropped attachment.

Thanks.

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